偏心竖向力作用下，单桩竖向承载力应满足的条件是（）<br>A:Qk≤R<sub>a</sub><br>B:<img src="/Image1/1b/1bcf18f4a5f3d8008611d52bd52286cd.jpg" />≤1.2R<sub>a</sub><br>C:Qk≤R<sub>a</sub>且<img src="/Image1/1b/1bcf18f4a5f3d8008611d52bd52286cd.jpg" />≤1.2R<sub>a</sub><br>D:<img src="/Image1/61/61ff2d446d13cf7e6611f136f50af40d.jpg" />≥0